Clutch control mechanism



June 8, 1937. E. G. HILL 250813,53()

vCLUTCH CONTROL MECHANISM Filed oct. 22, 1934 2 sheets-sheet 1 2 Sheet's-Shee c 2 E. G. HILL CLUTCH CONTROL MECHANISM Filed oct. 22,v 1934 Junes,1937.

Patented June 8, 1937 PATENT OFFICE' 2,083,530 CLUTCH CONTROL MECHANIYSM Edward G. Hill, South Bend, Ind., assignor to Hill Engineering Corporation, Richmond, Va., `a. corporation oi.' Virginia 'Application October 22, 1934, Serial No. 149,451 28 Claims. (Cl. 15m-.01)

This invention relates to clutch control mechanisms for motor vehicles.

In my prior Patent No. 1,964,693, issued June 26, 1934, I have described and claimed a valve mechanism which is particularly emcient in operation for controlling the clutch of a motor vehicle; The valve mechanism includes a pair of relatively movable valves,A one controlled by movement of the accelerator pedal and the other in accordance with the operation of the power device, the first named valve being movable in one direction to actuate the power device and disengage lthe clutch and movable in the other direction for :releasing the clutch for movement into operative engagement. The second valve operates in conJunction with the rst named valve to cut oi communication between the power device and the atmosphere to check the movement of the clutch elements usually at the point of initial engagement, andthe second named valve acts as a follow-up in conjunction with the iirst named valve to control engagement of the clutch elements in accordance with the rate of operation of the accelerator.

The control valves referred to have been found particularly satisfactory and eiiicient in operation for providing rapid clutch disengagement upon the releasing of the accelerator pedal and smooth engagement of the clutch elements upon depression of the accelerator, provided the accelerator is not operated faster than a predetermined speed. For all ordinary operations of the accelerator it is not necessary to operate the accelerator faster than the predetermined speed referred to,

except possibly in high gear, and accordingly the two cooperating valves referredA to are capable of fully controlling the operation of the clutch.

However, many drivers follow the practice of operating the accelerator relatively rapidly in 4u order to secure rapid vehicle acceleration, and in order to govern operation of the valve mechanism to prevent too rapid engagement ofthe clutch, the. prior construction referred to employs what may be termed the second check valve which operates to take the control of the clutch engaging function away from the cooperating -valves referred toto prevent too rapid clutch' engagement upon the relatively rapid operation of the accelerator. However, it is the common practice l in the conventional operation of a vehicle to coml pletely-release the clutch pedal relatively rapidly when in high gear, which operation is wholly pos'- sible without any jerking or lunging o f the vehicle, due to the fact that when the shift is made into high gear, the vehicle is traveling under substantial momentum. Accordingly, it is not desirable to retard too greatly the engagement of the clutch elements when the vehicle is in high gear.

An important object of the present invention is to provide means for controlling a power device connected to a vehicle clutch for effecting disengagement and thenengagement of the clutch,

with proper control means for preventing the too rapid engagement of the clutch elements in first, second and reverse gears, and to provide means for rendering the control means inoperative when the vehicle is in high gear to permit clutch engagement to take place relatively rapidly.

A further object is to provide a device of the character referred to having control means oper- A further object is to provide a-control valve mechanism for a differential pressure power device connected to a motor vehicle clutch, together with means operable under mostconditions for limiting the speed of movement of the clutch elements into engagement with' each other by limiting the rate at which pressure equalization can be established in the power device, and to provide means for rendering said last .named means inoperative to permit relatively rapid clutch engagement when the vehicle is in high gear.

A further object is to provide acontrol valve mechanism of the character' referred to Operative for exhausting air from one side of the power device and having an atmospheric passage provided with a control or second check valve normally operative for limiting the admission of air into the power device upon the relatively rapid operation of the accelerator, and to provide means in said passage for admitting air thereto independently of said second check valve to prevent the latter from limiting the admission of air into the power device when the vehicle is in high gear,

but thus permit relatively rapid clutch engagement.

Other objects and advantages of the invention will become apparent during the course of the Lof the invention. In this showing:

Figure 3 is a detail sectional View of an auxiliary control valve taken on line 3--3 of Figure 4, Figure 4 is a sectional view taken substantially on line 4-4 of Figure 2, y

Figure 5 is a diagrammatic view illustrating the electrical connections for the apparatus, and,

Figure 6 is a diagrammatic view illustrating a modication of the wiring connections.

Referring to Figure 1, the numeral I0 designates the manifold of a motor vehicle engine having a riser II provided witha carbureter I2 at its upper end. A throttle I3 controls the admission of fuel into the manifold and is mounted upon the usual shaft I4. An arm I5 is connected at one end to the shaft I4, and at its other end the arm I5 is connected to one end of an operating rod I6 having a return spring I1. The rod I6 is actuated in the usual manner by an accelerator pedal I8.

The vehicle is provided with the usual clutch Y.

(not shown) operated by the usual clutch shaft I9. An arm 20 is operatively connected to the shaft I9 to transmit movement thereto. A pedal 2| is loosely mounted on the shaft I9 and is provided with a lug 22 engageable with the arm 2.0 when the pedal 2l is depressed, to effect disengagement of the clutch. It will be apparent that the arm 20 is movable for eiecting clutch disengagement without transmitting movement to" the pedal 2l.

A power device indicated as a whole by the numeral 23 is employed for actuating the arm 20. 'The power device may be of the type illustrated in my prior patent referred to including a pair of casing sections 24 and 25 having a diaphragm 26 clamped therebetween and secured to one end of a pull rod 21. The rod 21 may be connected in any suitable manner to the arm 20, as through a ilexible member 28. vThe casing section 24 is in constant communication with the atmosphere through any suitable means such as a port 29, and the casing section 25 is adapted to be connected to a source of vacuum in a manner to be described, through a pipe or conduit 30.

The numeral 3l designates a valve casing or cylinder having a pair of concentric relatively slidable valves 32 and 33 therein. The valve 33 is provided with a stem 34 extending through the head 35 of the valve cylinder 3| and provided at its upper end with a knob 36. A cam 31 is carried by the throttle shaft I4 and operates to move the valve 33 downwardly to the position shown in Figure 1 when the throttle is in idling position. The cam is shown in Figure 2 in the position corresponding to the fully open throttle position, and as the throttle moves toward open position the cam 31 releases the stem 34 for upward movement. A spring 38 surrounds the stem 34 and tends to move the latter upwardly together with the valve 33.

The valve 33 is provided with opposite arcuate ports 39 toward its upper end, and an arcuate atmospheric port 40 is formed in the valve 33 at a point spaced a substantial distance below the ports 39. The valve 33 is provided with a cutout portion 4I adapted to communicate with the ports 40 or 39 or to assume a neutral position out of communication with both sets of these adapted to establish communication between a passage 42 and an elongated port 43, bothformed in the casing 3| at opposite sides thereof. 'Ihe port 40 is adapted under certain conditions to establish communication between the port 43 and an 'atmospheric passage 44 (see Figure 4). The passage 44 communicates with the atmosphere through a restricted passage 43', the effective area of which is adjustable by a screw 44.'.

'I'he passage 42 communicates with the intake manifold through a pipe 45 and avalve 46 controis; communication through the passage 42. This valve forms the armature of a solenoid 41 arranged in a casing 48', preferably formed integral with the casing 3l, and a light spring 49 is preferably employed for urging the valve 46 downwardly to closed position. The solenoid is adapted to be energized in a manner to be described to open the passage 42, and under other conditions, the solenoid 41 is deenergized to permit the valve 46 to close and thus render the valves 32 and 33 ineiective.

The lower end of the valve housing 3l is provided with a circular enlargement 50 forming one of a pair of complementary casing sections, the other of which is indicated by the numeral 5I.

` A diaphragm 52 is clamped between these casinfluenced by the vacuum communicated to the power device. The port 43 communicates with a passage 58, leading to the conduit 30, and the chamber 51 communicates with the passage 53 through ports 59 and 60, formed in the casing section 5I and diaphragm 52 respectively, and through a small passage- 6I.

Referring to Figure 4 the numeral 62 designates an extended portion of the casing 3| extending laterally therefrom. The outer portion of the extension 62 is provided with a chamber 63 communicating with the atmosphere through a relatively large port 64. A valve 65 is engageable in a seat 66 to disconnect the chamber 63 from the passage 44. The valve 65 is mounted on a stem 61 suitably guided for axial movement in the chamber 63.

The outer end of the extension 62 is provided with a circular enlargement 68 forming one of a pair of casing sections the other of which is indicated by the numeral 69. A diaphragm 10 is clamped between the casing sections 68 and 69 and is secured at its central portion to the valve stem 61, as at 1I. The interior of the casing section 68 obviously is in constant communication with the atmosphere through the chamber 63 and the port 64. The casing section 69 is provided with an axial extension 12 receiving the outer end-of a compression spring 13. The inner end of this spring seats against the diaphragm 10 to urge the valve 65 toward closed position, andsuitable screw adjusting means 14 extends through the outer end of the extension 12 to engage against and adjust the tension of the spring 13. A passage 16v has one end communicating with the passage 59, and the other end of the passage 15 communicates with the chamber formed within the casing section 69 through ports 16 and 11 formed respectively in the casing section 69 and diaphragm 10.

The elements'of the device previously described form the subject matter of my prior Patent No.

l1,964,693, previously described, and inrigures s and 4 the valve mechanism constituting the improvement forming the subject matter of the present invention is illustrated in detail. A conduit 18 of substantial area vis formed integral with the valve housing and communicates at one end with the passage 44. It will be apparent that the functioning of the passage 18, in a manner to be described, cannot be affected by the position of the valve 85, since the passage 18 is arranged between the valve 88 and the valve 83. At its other end, the passage 18l communicates with the interior of a small valve cylinder 18, and opposite the passage 18, the cylinder 18 communicates with the atmosphere as at 88.

A valve 8| is arranged in the cylinder 18 and is carried by a reduced stem 82. The upper end of the stem 82 is connected to an armature 88 operable in a solenoid 84. This solenoid may -be arranged within a casing secured to the main valve casing as at 88. Energization of the solenoid 84 moves the valve 8| to a position closing communication between the port 88 and passage 18, while deenergization of the solenoid drops the valve-8| to the position shown in Figure 8 to open communication between the port 88 and passage 18. A light spring 81 may be employed for insuringv downward movement of the valve 8| upon deenergization of the solenoid 84.

A wiring 'diagram for the electrical elements of the device is illustrated in Figure 5. The vehicle batteryeis indicated 4by the numeral 88 and is grounded at one side as at 88. The other side of the battery is connected to an ignition switch 88 which is movable into closed position into engagement with a contact 8|. This contact is connected to the ignition system (not shown) in accordance with the usual practice. The` contact 8| is connected by a wire-82 to' a switch 88 engageable with a contact 84. As will become apparent, the switch 88 constitutes a lock out switch for the clutch control mechanism whereby the opening of the switch prevents automatic operation of the clutch to permit foot operation thereof. A wire 88 is connected at one end to the contact 84 and at its opposite end to one of the terminals of the solenoid 41. In this connection it will be noted that the solenoid 41, in practice, is constructed substantially in accordance with the showing in Figure 2 with the casing 48 integral with the casing 4|, and for the purpose of illustration, the solenoid has been shown separate from the valve casing in Figure 5, arranged in the conduit 48.

The other terminal of the solenoid 41 is connected to a wire 88 leading to a button switch 81 arranged on the gear shift lever 88 associated with-the usual gear set 88. The lever 88 is indicated as being grounded as at |88. A wire |8| lleads from the wire 88 to a switch |82 engageable |88 is connected between the wire I8| and an arcuate contact |81 associated with the speedometer |88. The contact |81 is grounded as at |88 and is engageable by a brush ||8 operable by the speedometer in accordance with vehicle speed. 'Ihe brush ||8 remains in engagement -with the contact |81 from zero vehicle speed up ments into operative engagement.

to any predetermined maximum speed, such as from 8 to 10 miles per hour.

A switch'Ill has one end supported with respect to the gear set 88 and is normally in engagement with a contact ||2 grounded as at H8. The second and high gear shift rod ||4 of the gear set-moves forwardly when the gear shift is in high gear position to move the switch out of engagement with the contact ||2. The switch is connected to the wire 88 by a wire The solenoid 84 has one terminal connected byA a wire ||8 to the wire 85. A second switch arm ||1 is carried by and insulated from the switch as at ||8 and the upper end of the switch ||1 turns inwardly as at ||8 for normal engagement with the contact H2. A wire |28 connects. the switch arm ||1 to the other terminal of the solenoid 84. e

The operation of the apparatus is as follows:

The operation of the valvs 82, 33 and 85 is described in detail in my prior Patent No. 1,964,693, referred to above. When the throttle is in the idling position shown in Figure 1, the high point of the cam 31 holds the valve 82 in its lowermost position, in which case, communication is afforded between the power device and the intake manifold between pipes 88 and 35, through ports 38 and the reduced portion 4| of the valve 82. The partial vacuum existing in chamber 48 due to communication between this chamber and the passage 58 holds the diaphragm 52 and valve 82 in their lower positions, but since the valve 88 is also in its lowermost position, the port 48 will be arranged beneath the reduced valve portion 4|. to disconnect the port 48- from the atmosphere. l

Upon opening movement of the throttle I8 incident to depression of the accelerator pedal i8, the high point of the cam 81 will move away from the button 38, thus permitting the valve 38 to move upwardly. This action cuts off communication between the-power device and the manifold |8 and opens the power device for limited communication with the atmosphere through port 48 and the cut out valve portion 4|, passage 44 (see Figure 4), chamber 88 and port 84. The clutch, elements. will immediately move toward engaged position and during their initial movement, a partial vacuum will be retained in the diaphragm chamber 51 to prevent substantial upward movement of the valve 32. Upon the initial contacting of the clutch elements, a slight increase in pressure will occur in the chamber 51, thus permitting sufllcient further upward movement of the valve 82 to close the port 48 and thus disconnect` the power device from the atmosphere and arrest the movement of the clutch elements, provided the accelerator pedal is initially slightly depressed and then stopped. Ii the accelerator pedal is progressively depressed, the clutch elements will be retarded instead of arrested since the valve 83 will be progressively moving upwardly to maintain a slight c'orn- -munication between the atmosphere and the power device through the port 48. The degree of such communication, and hence the rate of movement of the clutch elements will depend upon the speed of movement of the valve 88. Obviously the slower the movement of the valve 88 the less will be the degree of communication with the atmosphere through port 48 and the slower will be the movement of the clutch eieopening movement of the throttle transmits a More rapid 55 valves 32, 33 and 65 and the port 43. will be impossible for the driver to -cause anyk correspondingly more rapid movement to the valve 38, thus tending to maintain anincreased degree of communication between the power device and the atmosphere to permit a more rapid 5 clutch engagement. V

Accordingly it will be apparent that the valves 32 and 33 are operative for controlling the movement of the clutch elements from the fully disengaged to the fully engaged position, and this is l true except upon the relatively rapid opening of the throttle when the vehicle is in first, second or reverse gears. In such gears, it is desirable to provide means for preventing too rapid clutch engagement with the consequent jerking or lunging l of the vehicle, which would occur upon rapid operation of the throttle. For this reason the valve 65 and associated parts 'are provided. The diaphragm is influenced by the degree of vacuum in the power device through the passages and 58, and a relatively slight degree of vacuum is suillcient to hold the valve 65 in open position. Under ordinary conditions of operation of the throttle a sufficient partial vacuum exists in the casing section 69 to prevent the closing-of the valve 65, and under such conditions clutch operation is controlled wholly by the valves 32 and 33. Upon theA relatively rapid opening movement of the throttle, however, the substantial and rapid increase in pressure resulting from the rush of air through port 48 reacts through the passage 15 to reduce the differential pressure on opposite sides of the diaphragm 10 sulciently to permit the closing of the valve 65, thus preventing the unrestricted flow of air into the power device, Under such conditions, the admission of such air is restricted by the port 43', thus retarding the movement of the clutch elements and preventing the grabbing thereof.

The foregoing operation takes place if the valve 40 8| is in closed position, since the passage 44 communicates with the .atmosphere only through the passage 43 if both of the valves 65 and 8I are closed. The circuit for the solenoid 84 includes the source 88, switches 80 and 93, wires 85, II6 45 and |20, switch II1 and contact II2 and grounds II3 and 89, The 'switch end' I I8 remains in engagement with the contact I I2 at all times except when the gear set is in 'high gear, and accordingly the solenoid 84 is energized whenever the vehicle is in first, second or reverse gears. Under such conditions, the'solenoid 84 holds the valve 8| in closed position, and the admission of air into the power device upon the depression of the accelerator pedal is controlled wholly by the Thus it grabbing ofthey clutch elements by suddenly depressing the accelerator pedal to a substantial extent, when the vehicle is in first, "second or repoint substantially corresponding to vehicle speed.

This depression of the accelerator pedal takes place relatively rapidly and ordinarily to a sub stantial extent, and the principal object' of the p'resent invention is to provide means operable,

under such conditions for preventing the operation of thesecond check valve 65 to permit the` clutch elements to move relatively rapidly from the fully disengaged to the fully engaged position.

When the shift is made into high gear, the shift rod II4 moves the switches III and II'I out of engagement with the contact I I2, and the circuit 5 for the solenoid 84 is thus broken. Deenergization of the solenoid 84 drops the valve 8l to the open position shown in Figure 3, thus opening communication between 'the port 80 and passage 18. If the operator then depresses the ac- 10 celerator relatively rapidly and to ,a substantial extent to accelerate the motor speed to a point corresponding to the vehicle speed, the drop in differential pressure in the power device will release the diaphragm 10 for downward movement, 15 thus closingv the valve 65. 'I'his operation, however, will not affect the movement of the clutch Aelements since air will be admitted into the power device through the port 88 and passage 18 and the rate of clutch engagement will depend wholly 20 upon the rate of operation of the valve 33. 'Ihus the valve 18 functions to permit relatively fast clutch engagement in high gear, which is highly desirable.

Thus the valves 32, 33, 65 and 8| cooperate with 25 each other to provide the desired results under all gear shifting conditions. In all gears, the valves 32 and 33 control the entire operation provided the accelerator pedal is not depressed relatively rapidly, and under such conditions, the 30 valves 65 and 8l do not aiect clutch operation. The valve 65 functions to prevent the grabbing of the clutch elements andis rendered operable in first, second and reverse gears by the closing of the valve 8I. The latter valve, however, moves 35 to open position when the vehicle is in high gear to prevent the functioning of the valve 65.

With the electrical system described, it will be apparent that the solenoid 84 is deenergiz'ed at all times when the vehicle-is in high gear, regard- 40 less of any otherl conditions, and the valve 8l accordingly remains in open positin during such times. As an alternative system, the wiring larrangement illustrated in Figure 6 may be employed, and this system takes care of a condition 45 which should be considered in the controlling of the vehicle. Referring to Figure 6 it will be noted that the switch II1 is eliminated, and the leads II6 and I20 of the solenoid 84 are connected across the wires 85 and 96. Accordingly the sole- 50 noid 84 is in parallel with the solenoid 41. Thus it will be apparent that when the vehicle is in high gear, the switch IIIls open, and when the shift is made to high gear at substantial vehicle speeds, the operator may depress the accelerator pedal rapidly and to a. substantial extent, and the movement of the clutch elements will be wholly controlled by the valves 32 and 33. If the shift into high gear is made at a relatively low vehicle 60 speed, however, it is not desirable to take the control of the movement of the clutch elements away from the valve 65, since at low vehicle speeds some jerking of the clutch elements may occur. With the system shown in Figure 6. the 05 circuit through the solenoid 85 is established, when the vehicle is in high gear, if the brush .I Ill .is in engagement with the contact |81, and under such conditions, the solenoid 84 will be energized to hold the valve 8I in closed position. Thus 7 it will be apparent that the operation of the valve 8l will .be dependent chiefly upon the position of f the gear shift lever, but it wil1-be held in closed position even in high gear if the vehicle is travelaosasao is in first, second and reverse gears, the circuit being completed through wires 90 and H5, switch III, contact H2 and ground H9. This circuit is broken when the vehicle is in high gear, but the shunt circuit from the wire'90 to ground, in cluding wires |0| and' |00, contact |01 and brush H0, maintains the solenoid 41 energized in the lower vehicle speeds when the gear shift lever is in high gear position. Above the predetermined speed at which the circuit is completed between the contact |01 and brush H0, the solenoid 41 will be deenergized, thus rendering the valve mechanism wholly inoperative. Under 'such conditions'declutching will not occur upon the releasing of the accelerator pedal and the I vehicle engine is permitted to be used as a brake.

When the accelerator is released at higher vehicle speeds in high gear. the clutch will thus remain engaged vuntil the vehicle is decelerated to the point at which the brush ||0 engages contact |01 'at which point the solenoid 41 will be energized to open the valve 46 and communication between'the power device and the intake manifold will be completed and declutching will occur.

Full free wheeling is provided by closing the switch |02 in which case the circuit from the wire 98 to the ground will be constantly maintained regardless of the position of the gear shift lever or the brush H0, and declutching. will occur at each releasing of the accelerator, regardless of vehicle speed or the position of the gear shift lever. The button 91 is provided to permit declutching' to occur at the will of the operator whenever desired. For example, when a vehicle is ascending a steep grade the operator may desire to shift to second gear without awaiting vehicle deceleration to the point at which the brush H0 will engage the contact |01, and under s'uch conditions, the operator may depress the button 91. This action completes a third shunt circuit from'wire 96 to button 91, gear shift lever 99 and ground |00. The solenoid 41 will thus be energized and the releasing of the accelerator pedal will effect declutching, whereupon the operator may shift into second gear. The use of the button 91, of course, is unnecessary when the switch |02 is closed, since the closing of this switch permits declutching to be eifected at each releasing of the accelerator pedal.

It is to be understood vthat the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

l. Clutch control mechanism for a motor vehicle including a clutch, comprising a power device connected to the clutch, control mechanism for effecting actuation of the power device to disengage the clutch and for variably effecting deactuation of the power device to engage the clutch, auxiliary control means automatically operative for limiting the rate of clutch engagement when said control mechanism tends to release the clutch for too rapid engagement, and means for rendering said auxiliary control means ineiective.

2. Clutch control mechanism for a motor ve- `hicle including a clutch and an engine having a throttle therefor, comprising a' power device connected to the clutch, control mechanism operative in conjunction with the'throttle for eecting actuation of the power device to disengage the clutch and for variablyeffecting deactuatlon of the power device to release the clutch for movement into operative engagement,auxiliary control means automatically operative for limiting the rate of clutch engagement when said control mechanism tends to release the clutch for too rapid engagement, and means for rendering said auxiliary control means ineffective.

3. Clutch control mechanism for a motor vehicle including a clutch andan engine having a throttle therefor, comprising a power device connected to theclutch, control mechanism4 operative for eifecting actuation and deactuatlon -of the power device for disengaging the clutch and for'releasing it for movement into operative engagement, said control mechanism including a movable member connected to the throttle to determine the rate of deactuatlon of the power auy device in accordance with the rate of opening I movement of the throttle. auxiliary control means for preventing too rapid engagement of the clutch upon the relatively rapid opening. movement of the throttle, and means for rendering said auxiliary control means ineffective.

4. Clutch control mechanism for a `motor vehicle including a clutch and an engine having a throttle therefor, comprising a power device connected to the clutch, control vmechanism for the power device including a pair of members one of which is operable by the throttle and the other in accordance with the degree of actuation of the power device and operativeV for effecting actuation and deactuatlon of the power device vfor disengaging `the clutch elements, and for releasing them for movement into operative engagement in accordance with the rate of opening movement of thethrottle, auxiliary control means operative for retarding the movement of the clutch elements into operative engagement when the throttle is opened relatively rapidly, and means for rendering said auxiliary control means ineifective.

5. Clutch control mechanism for a motor ve- 'hicle including a clutch and transmission, comprising a power device connected to the clutch, control mechanism for effecting actuation of said power device for disengaging the clutch and for releasing it for movement into operative engagement, auxiliary control means op- 'er'ative for retarding movement of the clutch for disengaging the clutch and releasing it for movement into engagement, auxiliary control means operable upon the relatively rapid opening of the throttle for preventing too rapid engagement of the clutch, and means operable by the transmission when the latter is in high gear for rendering said auxiliary control means ineffective.

7. Clutch control mechanism for a motor ve- 10 hicle including a clutch and transmission, and

and means operable by the transmission when I the latter is in high gear for rendering said auxiliary control means ineffective.

8. Clutch control mechanism for a motor vehicle including a clutch and transmission, and an engine having a throttle therefore, comprising a power device connected to the clutch, control mechanism for effecting actuation anddeactuation of said power device for disengaging the clutch and releasing it for movement into operative engagement., said control mechanism including a pair of elements, one operable by the throttle and the other by the power device -to release the clutch for movement to operative engagement in accordance with the rate of movement of the throttle, auxiliary control means operable for preventing too rapid clutch engagement upon the relatively rapid opening movement of the throttle, and means operable by the transmission when the latter is in high gear for rendering said auxiliary control means ineective.

9. Clutch control mechanismior a motor vehicle including a clutch, comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation of the power device to disengage the clutch and for variably effecting deactuation of the power device to release the clutch for movement into operative engagement, auxiliary control valve means automatically operable for limiting the rate of clutch engagement when said control valve mechanism tends to release the clutch for too rapidengagement, and a valve operable for rendering said control valve means ineective.

10. Clutch control mechanism for a motor vehicle including a clutch, and an engine having a throttle therefor, comprising a differential pressure power -device connected to the clutch, control valve mechanism operable in. accordance v with the rate of operation of the throttle for 11. Clutch control mechanism for aA motor vehicle including a clutch, and an engine having a throttle therefor, n comprising a diierential pressure power device connected to the clutch, a control valve mechanism for eiecting actuation and deactuation of the power device for disengaging the clutch and releasing it for movement into operative engagement, said control valve mechanism including a main valve operable by the throttle to control clutch engagement in ac- Y cordance with the rate of opening movement of the throttle, auxiliary controlvalve means for preventing too rapid engagement of the clutch upon the relatively rapid opening movement of the throttle, and a valve operable for rendering said auxiliary control valve means completely ineffective.

12. Clutch control mechanism for a motor vehicle including a clutch, and an engine having a throttle therefor, comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and releasing it for movement into operative engagement, said control valve mechanism including a pair of cooperating valves one of which is operable by the throttle4 and the other of which is operable by the power device whereby the rate of movement of the clutch into operative engagement is controlled in accordance with the rate of opening movement of the throttle, auxiliary control valve means operable for preventing the too rapid engagement of the clutch -upon the relatively rapid opening movement of the throttle, and a valve operable for rendering said control valve means completely ineffective.

13. Clutch control mechanism for a motor vehicle engine including a clutch and transmission, comprising a diierential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of the power device for disengaging the clutch. and releasing it for movement into operative engagement, auxiliary control Valve means operable for preventing too rapid engagement of the clutch, and a valve operable by the transmission when the latter is in high gear for rendering said auxiliary control valve means ineffective.

14. Clutch control mechanism for a motor vehicle including a clutch and transmission, and an engine having a throttle therefor, comprising a differential pressure power device connected to the clutch, control valve mechanism operable in accordance with theV rate of operation of the throttle for effecting actuation and deactuation of the power device for disengaging the clutch and for releasing it for movement into operative engagement, auxiliary control valve means operable for preventing too rapid engagement of the clutch upon the relatively rapid opening movement of the throttle, and a valve operable by the transmission when the latter is in high gear for rendering said auxiliary control valve means ineiective.

15. Clutch control mechanism for a motor vehicle including a clutch and transmission, and an engine having a throttle therefor, comprising a dierential pressure power device connected to the clutch, a control valve mechanism for eiiecting actuation and deactuation of the power device .for disengaging the clutch and releasing it for movement into operative engagement, said control valve mechanism including a main valve operable by the throttle to control clutch engagement in accordance with the rate of opening movement of the throttle, auxiliary control valve means for preventing too rapid engagement of the clutch upon thefrelatively rapid opening movement of the throttle, and a valve operable by the transmission when the latter is in high gear for rendering said auxiliary control valve means ineffective.

16. Clutch control mechanism for a motor vehicle including a clutch and transmission, and an engine having a throttle therefor. comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and releasing it for movement into operative engagement, said control valve mechanism including a pair of cooperating valves one of which is operable by the throttle and the other of which is operable by the power device whereby the rate o f movement of the clutch into operative engagement is controlled in accordance with the rate of opening movement of the throttle, auxiliary control valve means operable for preventing the too rapid engagement of the clutch upon the relatively rapid opening movement of the throttle, and a valve operable by the transmission when the latter is in high gear for rendering said auxiliary control valve means ineffective.

17. Clutch control mechanism for a motor vehicle including a clutch, comprising a differential pressure power device connected to the clutch, control valve mechanism for eecting actuation of said power device to disengage the clutch and for variably effecting deactuation of said power device to releasethe clutch for movement into operative engagement, a fluid passage connected to the atmosphere for establishing pressure equalization in said power device when the latter is deactuated, a valve controlling communi'- cation through said fluid passage for limiting the rate of clutch engagement when said control valve mechanism tends to release the clutch for too rapid movement intooperative engagement, and a valve operative for opening said passage to the atmosphere independently of said last named valve for rendering the latter ineffective.

18. Clutch control mechanism for a motor vehicle including a clutch, comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device .for 'disengaging the clutch and for releasing it for movement into operative engagement, an atmospheric passage through which pressure equalization is established in said power device when the latter is deactuated, a valve controlling communica-A tion through said passage, means for closing said valve upon the relatively rapid reduction in the pressure differential in said power device, and a valve operable for affording communication between said passage and the atmosphere independently of said last named valve to render the latter ineffective.

19. Clutch control mechanism for a motor vehicle including a clutch, comprising a differential pressure power device connected lto the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and for releasing it for movement into operative engagement, a passage connected between the power device and the atmosphere for establishing pressure equalization therein, a valve controlling communication between said passage andthe atmosphere, a pressure responsive device connected to said valve and operable upon the relatively rapid reduction of the differential valve, and a' valve controlling communication between saidV passage and the atmosphere inde-4 pendently of said last named valve for rendering the latter ineffective.

20. Clutch control mechanism for a motor vehicle including a clutch and transmission, comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and for -releasing it for movement into operative engagement, a passage connected betweenthe power device and the atmosphere for reducing the pressure differential in said power device when the latter is deactuated, a valve controlling communication through said passage and movable to closed position upon the relativelyrapid reduction in the pressure dierential in said power device, and a valve controlling communication between said passage and the atmosphere independently of said last named valve and connected to the transmission to be opened thereby when the latter is in high gear.

21. Clutch control mechanism for a motor vehicle including a clutch and transmission, comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and for releasing it for movement into operative engagement, a passage connected between said power device and the atmosphere for reducing the pressure differential in said power device when the latter is deactuated, a valve controlling communication through said passage, means for closing said valve upon the relatively rapid reduction in the pressure differential inv said power device, and a valve controlling communication between said passage and the atmosphere independently of said last named valve and movable t'o closed position by the transmission when the latter is in high gear.

22. Clutch control mechanism for a motor vehicle including a clutch` comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and for releasing it for movement into operative engagement, said control valve mechanism including an atmospheric passage adapted to be opened by said valve mechanism to reduce the pressure differential in said power device when the latter is deactuated, a valve controlling communication between said passage and the atmosphere and operable for restricting communication through said passage upon the relatively rapid reduction in the pressure differential in said power device, and a valve controlling communication between said passage and the atmosphere independently of said last named valve and' movable to open position to render the latter ineffective.

23. Clutch control mechanism for a motor vev pressure in said power device for closing said valve, and a Valve controlling communication between said passage and the atmosphere independently of said last named valve and movable to open position'for rendering the latter ineiective.

24. Clutch control mechanism for a motor ve- A hicle including a clutch and transmission, combetween said passage and the atmosphere and operable for restricting communication through said passage upon the relatively rapid reduction in the pressure differential in said power device, and a valve controlling communication between said passage and the atmosphere independently of said last named valve and movable to open position by the transmission when the latter is in high gear.

25. Clutch control mechanism for a motor vehicle including a clutchand transmission, comprising a differential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of said power device for disengaging the clutch and for releasing it for movement into operative engagement, said control valve mechanism including an atmospheric passage adapted to be opened by said valve mechanism to reduce the pressure differential in said power device when the latter is deactuated, a valve controlling communication between said passage and the atmosphere, means responsive to a relatively rapid decrease in the diierential pressure in said power device for closing said valve, and a valve controlling communication between said passage and the atmosphere independently of said last named passage and movable to open position by the transmission when the latter is in high gear.

26. Clutch control mechanism for a motor vehicle including a clutch and transmission, comprising a power device connected to the clutch, control mechanism for e'ecting actuation and deactuation of the power device for disengaging the clutch, auxiliary control means operative for preventing the too rapid engagement of the clutch, means'for rendering said auxiliary control means ineiective when the vehicle is in high gear, and means for rendering said last named means ineffective when the transmission is in high gear and the vehicle is traveling below a predetermined speed.

27. Clutch control mechanism for a motor vehicle including a clutch and transmission, comprising a power device connected to the clutch, control mechanism for effecting actuation of said power device for disengaging the clutch and for releasing it for movement into operative engagement, auxiliary control means operative for preventing too rapid engagement of the clutch, means operable for rendering said auxiliary control means ineiective when the transmission is in high gear, and means for rendering said last named means ineffective when the transmission is in high gear and the vehicle is traveling below a predetermined speed.

28. Clutch control mechanism for a motor vehicle engine including a clutch and transmission, comprising a diierential pressure power device connected to the clutch, control valve mechanism for effecting actuation and deactuation of the power device for disengaging the clutch and for releasing it for movement into operative engagement, auxiliarycontrol valve means operable for preventing too rapid engagement of the clutch, a valve operable for rendering said auxiliary control valve means ineffective when the transmission is in high gear, and means for rendering said valve ineffective when the transmission is in high gear and the vehicle is traveling below a predetermined speed.

EDWARD G. HILL. 

